This invention pertains to a slider mechanism and, more particularly to such a mechanism which is self-locking and which can be used to hold telescopically adjustable members of a leg or stand in adjusted height position. The self-locking slider mechanism has a friction member movably mounted on one tubular member and frictionally engaging a second tubular member. The friction member has means associated with it to require a greater force manually applied lengthwise of the stand or leg to decrease the length thereof than to increase the length thereof, whereby height adjustment may be achieved while supporting a load. One use is for a music stand wherein a desk will support musical scores while still enabling manual height adjustment. The slider mechanism is also usable in other types of stands and adjustable leg structures.